Process for producing a packaing unit

ABSTRACT

A method for producing a packaging unit includes combining individual products into a product formation, providing a shrink-wrap film having a perforation area that is susceptible to contact-free activation, and using the shrink-wrap film, securing the individual products to each other.

RELATED APPLICATIONS

This application claims the benefit of the priority date of German application DE 10 2012 012 407.4, filed on Jun. 25, 2012 the contents of which are herein incorporated by reference.

FIELD OF INVENTION

The invention concerns a method for producing a packaging unit according to which individual products are combined into a product formation and are secured to each other by means of a shrink-wrap film. Also the subject of the invention is one of individual products combined into a product formation, the products being secured to each other by shrink-wrap film.

BACKGROUND

In producing packaging units, as described by the type-defining prior art according to DE 10 2008 052 633 A1, the shrink-wrap film or shrink film is wrapped around and then shrunk onto the product formation, with the formation of at least one lateral opening. In the area of this lateral opening, the shrink-wrap film is arranged with a closed surface in the form of a closure with overlapping fold areas. This reduces costs and leaves functionality unchanged.

To guarantee the stability of the aforesaid packaging units, manufacturers fall back not only on special closures as described in DE 10 2008 052 633 A1, but in practice, stabilization means are often used as a supplement or in addition. These could be cardboard bases, so-called pads or trays on which products, for example, are placed and combined into the product formation. After looping the packaging unit made in this way with the shrink film or shrink-wrap film, the necessary stability is indeed largely achieved. But this result is linked to the disadvantage that the packaging is not of a single type.

The products to be packed can be, for example, containers such as cans, bottles, tubes etc. Other products too, such as glasses with a screw closure, goods packages for foods etc., can form the relevant packaging unit. To now make the individual products accessible, it is necessary to undo the shrunk-on film, at least partially, for example to cut it or tear it etc. This often requires a level of force and is regarded by consumers as being inconvenient. For this reason, producers of such packaging units provide perforations already made in the film, to facilitate the tearing of the film and to allow easy access to the combined products. These perforations are mostly made mechanically with the help of, for example, blades during film production.

The known approach has a number of disadvantages. For example, the mechanical perforations can typically only be made in the film in the so-called rolling direction. This means that the strip of film transported in a longitudinal direction for the subsequent production of a length of film for wrapping around a product formation can typically only be given perforations in this longitudinal direction in a simple way and manner. Insofar as one may also want perforations in a crosswise direction or diagonally, the strip of film must be halted and/or moved at a reduced production speed. This increases production costs. In addition, in the subsequent shrink process in, for example, a shrink tunnel, the previously made perforations mechanically weaken the resulting packaging unit. This means that there is a danger that, during the subsequent transportation, the packaging unit made in this way tears unintentionally in the perforation area or in the area of the previously made perforations.

SUMMARY

The invention is intended to provide a remedy to the foregoing difficulties by providing a method and an associated device for producing a packaging unit by means of which the packaging unit can be produced with a high level of strength and at the same time, only a simple manipulation is required during opening.

A solution to this technical problem is a generic method for producing a packaging unit in which the film is furnished with at least one perforation area that can be activated in a contactless manner.

The perforation area is generally defined by a perforation coating applied to the film. The perforation coating can be specifically made brittle or made weaker by an energy source. In fact, the invention opens up the possibility of reducing the strength of the film in the perforation area by more than 5% after activation with an energy source working in a contactless manner. Strength in the context of the invention means the tensile strength and/or tear strength of the shrunk-on shrink-wrap film.

Some embodiments include furnishing the film in a first step with the previously mentioned perforation coating. The perforation coating can then be activated in a second downstream step. This second step can directly follow the film shrinking operation. The first step can, in contrast, be carried out before the shrinking of the film or only after it. It is however also possible to carry out the activation of the perforation coating only much later, for example only after the transportation of the packaging unit to its destination. This means that the energy source regularly needed and working in a contactless manner to activate the perforation coating is, in a first variant, arranged for example behind or even immediately behind a shrink area or a shrink tunnel. In this case, the packaging unit leaves the device for its production with the film shrunk on and the perforation area defined on the film or with the desired perforations.

The last of these variants mentioned however corresponds to the energy source as a component of the device for producing the packaging unit being arranged physically under certain circumstances at a large distance from the actual shrink tunnel or the shrink area. In fact, the energy source can be provided at the place of processing of the packaging unit. In this case, the perforation coating is only activated immediately before the further processing of the packaging unit.

In this way, for example, during the transport of the packaging unit, the unchanged strength of the film is provided and is weakened specifically in the perforation area only immediately upon opening the packaging unit. Moreover, the opening of the packaging unit can be carried out generally by for example warehouse personnel to remove the products from the packaging unit and to place them, for example, on a shop shelf. Then, the destroyed length of film can be collected as a single material type and recycled.

However, it is equally possible for only the final consumer to break open the packaging unit or to open the shrink-wrap film in the area of the perforations, in order then to remove the products. It is furthermore feasible for the end consumer to have, for example, a mobile energy source. In this case too, the destroyed length of film can be recycled as a single material type as, because of the increased strength present during the transport, additional stabilisation means are as a rule unnecessary.

In this connection, it is guaranteed in any case that the products combined into the product formation do not experience any damage from, for example, blades or other splitting devices in the opening step of the shrunk-on film. This means that the products are available at the desired quality and with undamaged packaging. Moreover, no product damage is observed during transportation as the packaging unit produced according to the invention cannot be opened unintentionally. Instead, the activation of the perforation coating can be set for a defined time and optionally specified.

To carry out the activation in detail, various options are provided in the context of the invention. Thus, the perforation coating can be made absorbent in terms of the energy source. Due to the absorption of the energy emitted by the energy source, the perforation coating is generally heated in the course of its activation. This heating can be confined to local areas, which represent the previously defined embrittlement areas, within which the shrunk-on film can be easily opened.

Alternatively to this so to speak thermal activation of the perforation coating by energy introduced contactlessly, it is possible as an alternative or in addition, to start a chemical reaction between the perforation coating and the film by means of the energy. For example, the perforation coating can be made to be oxidising, whereby the start of a corresponding oxidation process of the perforation coating occurs by means of the energy source. The oxidation and the usually associated emergence of (oxygen) radicals now results in the film experiencing the desired specific weakening at least in the area of this perforation coating. This can occur in detail in such a way that the perforation coating contains hydrogen peroxide that is activated by, for example, specifically introduced heat by an infra-red source or generally a heat source as the energy source. The hydrogen peroxide activated in this way decomposes and the radicals thereby forming ensure that the film is specifically weakened in the area of the perforation coating.

In general, the energy source used is an electromagnetic radiation source. Moreover, this can be a UV radiation source, a microwave radiation source, an X-ray source or particularly preferred a laser radiation source. The perforation coating is in this case in each case made so that the relevant rays are absorbed and converted into heat energy. For example, the perforation coating can be furnished with constituents that absorb the infra-red radiation of an infra-red laser and in this way are heated. Feasible in this connection are, for example, carbon particles, metal particles etc.

Alternatively or additionally, it is however also possible for the energy source to work inductively and/or capacitively. In this case, the perforation coating is as a rule made to be conductive, whereby at this point, for example, transparent conducting oxides (TCO) can be used. A conducting coating of this kind is, for example, heated by inductively or capacitively coupled energy, so that once again the film is embrittled in the desired way and manner in places or in the area of the perforation coating. Examples of such transparent conducting oxides are inter alia indium tin oxide (ITO), fluorine-doped tin oxide (FTO) or indeed aluminium zinc oxide (AZO) and antimony tin oxide (ATO).

In any case, the construction in the context of the invention can occur and be undertaken so that the strength of the film in the perforation area is reduced by more than 5% after activation. Categorically, the strength of the film can also experience a specific reduction by 10% or even more. Moreover, the perforation coating is generally applied on an upper film surface. In general, this upper film surface is moreover furnished with an overprint, such as an advertising overprint, product information etc. In this way, an associated printed image can be produced in one operation by means of an associated print station. This printed image contains both information about the individual products and also the perforation coating, which can be activated after the shrink operation. This means that the perforation coating can be designed as a printed coating. As already explained, the activation can be carried out immediately after the shrinking-on of the associated film strip around the product formation or chronologically shortly before the handover of the packaging unit to the recipient of the goods.

In this connection, it is clear that the printed image in its entirety comprising the advertising message and/or production information and/or the perforation coating is produced on the film by an electronic control by means of the print station or at least one print unit. In most cases, the printed image is applied on a continuous strip of film, whereby the strip of film is then generally cut in a crosswise direction into individual lengths of film and then looped around the product formation and shrunk on.

Instead of the described electronic control of the one or more print units of the print station to produce the printed image, in theory, a so-called print mask can be used. In any case, the upper film surface is regularly furnished complete with the printed image, which, at the same time, contains the perforation coating at the desired location. This is ensured by the print unit in conjunction with a control installation in which the associated printed image may be deposited. It is clear in this connection that, by means of the control installation, the printed image can of course be changed and adapted to actual requirements. Moreover, in the context of the invention, if necessary in the perforation area or before application of the perforation coating, a pre-perforation can be used, which, for example, can be defined mechanically. By means of the pre-perforation, large perforation areas can also basically be described.

As a result, a method for producing a packaging unit is provided by means of which a stable packaging unit can be defined which can be opened both easily and conveniently. In contrast to approaches hitherto, the packaging unit according to the invention can be furnished with one or more perforation areas that can be arranged at any location on an associated length of film. This means that, according to the invention, the perforation area can be specified and located regardless of the rolling direction of the associated strip of film. In this way, the flexibility is considerably increased.

At the same time, additional stabilization means for the packaging unit are generally made unnecessary by using a film that is strong enough to secure the products perfectly to each other in the shrunk-on state. Any perforations can be activated only at the place of use. In this way, damage to the packaging unit according to the invention arising during transportation can be ruled out from the outset. This is where the main advantages are to be found.

In one aspect the invention features a method for producing a packaging unit. Such a method includes combining individual products into a product formation, providing a shrink-wrap film having a perforation area that is susceptible to contact-free activation, and using the shrink-wrap film, securing the individual products to each other.

Some practices also include causing contact-activation of the film at the perforation area using an energy source, thereby reducing film strength at the perforation area. Among these are practices in which reducing film strength includes reducing film strength by more than 5% in the perforation area after contact-free activation thereof.

Other practices further include furnishing the shrink-wrap film with a perforation coating, and causing contact-free activation of the perforation coating. Among these are those practices in which furnishing the shrink-wrap film with a perforation coating includes applying the perforation coating on an upper film surface of the film and those other practices in which furnishing the film with a perforation coating includes printing a coating on the film. Among these are practices in which printing a coating on the film is carried out after securing the individual products to each other.

Also among these practices are those in which furnishing the film with a perforation coating includes furnishing a perforation coating that absorbs a selected form of energy. Among these are practices that include heating the film by providing the selected form of energy to be absorbed by the film.

Yet other practices of the invention include those in which furnishing the film with a perforation coating includes furnishing a perforation coating that engages in a chemical reaction in response to a selected form of energy.22. The method of claim 13, wherein causing contact-activation of the film at the perforation area using an energy source includes causing contact-free activation using electromagnetic radiation.

Among other practices of the inventive method are those in which causing contact-activation of the film at the perforation area using an energy source includes causing contact-activation using inductively-stored energy, and those in which causing contact-activation of the film at the perforation area using an energy source includes causing contact-activation using capacitively-stored energy.

In another aspect, the invention features a manufacture including a packaging unit including individual products, and a shrink-wrap film. The shrink-wrap film is furnished with a perforation area. The individual products are combined into a product formation, wherein the products are secured to each other by the shrink-wrap film, and wherein the perforation area is susceptible to contact-free activation.

DESCRIPTION OF THE DRAWING

The invention is explained in more detail below by means of a drawing illustrating just one example of an embodiment. The single FIGURE shows one packaging unit that was made by the method according to the invention and using an associated device.

DETAILED DESCRIPTION

The FIGURE shows a packaging unit that secures the individual products 2 combined into a product formation 1 to each other using a shrink-wrap film 3. In the illustrated embodiment, the film 3 is furnished with two perforation areas 4.1 and 4.2, that, in each case are susceptible to contact-free activation and that are illustrated in the FIGURE. However, in some embodiments, the film 3 may have only one perforation area.

The production of the packaging unit shown in the single FIGURE occurs in such a way that a strip of film stretched out along its length is transported in a longitudinal direction by an associated, and not illustrated, device During this transportation, the film is furnished with a printed image 4.1, 4.2. This printed image 4.1, 4.2 comprises, in the example of the embodiment but not restrictively, two perforation coatings 4.1, 4.2 that, after their activation, define the perforation areas 4.1, 4.2. In addition, the printed image generally also includes one or more advertising overprints and product information that have been left out of the single FIGURE for reasons of clarity.

In any case, the printed image 4.1, 4.2 is applied to an upper film surface by a print station. In some embodiments, the print station has a print unit. In other embodiments, the print station is fitted with a plurality of print units, 4.1, 4.2, one of which is for the perforation coatings and other of which is for advertising overprints and product information.

After producing the printed image 4.1, 4.2, the strip of film is generally cut crosswise into a plurality of lengths of film. A particular length of film is looped around the production formation 1 and then shrunk on in a shrink tunnel, which is not illustrated. Immediately following this shrink tunnel, an energy source, likewise not illustrated, can be provided in the device, by means of which the perforation coating 4.1, 4.2 is activated, thereby causing the perforation area 4.1, 4.2 to arise. It is however also possible to design the energy source physically separately from the shrink tunnel, so that the activation of the perforation coating 4.1, 4.2 occurs, for example, chronologically shortly before the handover of the illustrated packaging unit to a recipient of goods. In this connection, even a mobile energy source is possible.

The activation of the perforation coating 4.1, 4.2 in the perforation area 4.1, 4.2 occurs by the previously mentioned and energy source working in a contactless manner. The energy source in one example is an infrared laser. The perforation coating 4.1, 4.2 may be embodied in each case as a print coating, and in particular, as an inkjet-printed coating. The ink applied is one that is furnished with materials that are absorbent in the infrared. For example, the ink can contain carbon and/or metal particles that are heated using the infrared laser as an energy source. This heating activates the perforation coating 4.1, 4.2. As a result, the film 3 is specifically made brittle in the area of the perforation coating 4.1, 4.2. In this way, the strength of the film 3 is reduced in the perforation area 4.1, 4.2, for example, by values of more than 5% compared with the film 3 outside the perforation area 4.1, 4.2.

In one embodiment, the perforation area or the perforation coating 4.1, 4.2 is designed as a line or as a linear shape. The individual line is defined by relevant perforation points that, in the example, are applied onto the film 3 by an inkjet printer. Other activation measures are of course also feasible and are included in the invention, as already described earlier.

In the course of activation by the infrared laser, the particular points defining the linear perforation coating 4.1, 4.2 absorb the infrared radiation emitted by the laser. This causes local heating of the perforation coating 4.1, 4.2 and likewise causes local embrittlement of the film 3. In this way, after the activation, the associated perforation area 4.1, 4.2 is provided and the film 3 can be easily torn along the perforation lines produced. As the activation of the perforation coating 4.1, 4.2 occurs typically after the transportation of the illustrated packaging unit, the film 3 has its unrestricted strength during the transportation, so that there is no fear of damage to the products 2. This also applies when the film 3 is torn along the perforation lines. In this case too, the products 2 are not subject to any damage and can be removed from the packaging unit without difficulty.

In this way, it is particularly advantageous if the perforation coating 4.1, 4.2 takes place after the covering of the containers with the shrink-wrap film (2). The reason for this is that each material application fundamentally damages and generally complicates film handling, e.g. by an increased adhesion (tack) of the films (2) in the area of the coating. This can all be prevented if the material is made in accordance after the first covering in the stamping station before the shrink tunnel. The energy source of the shrink tunnel can then be used for processing steps such as drying and hardening. Alternatively, the coating can also take place after the shrink tunnel at a suitable activation or drying station. Where an application head, which can be moved in the x-y-z direction is used, e.g. a robot arm, any perforation pattern can thus be provided on the container. 

Having described the invention, and a preferred embodiment thereof, what is claimed as new and secured by Letters Patent is: 1-11. (canceled)
 12. A method for producing a packaging unit, said method comprising combining individual products into a product formation, providing a shrink-wrap film having a perforation area that is susceptible to contact-free activation, and using said shrink-wrap film, securing said individual products to each other.
 13. The method of claim 12, further comprising causing contact-activation of said film at said perforation area using an energy source, thereby reducing film strength at said perforation area.
 14. The method of claim 13, wherein reducing film strength comprises reducing film strength by more than 5% in said perforation area after contact-free activation thereof.
 15. The method of claim 12, further comprising furnishing said shrink-wrap film with a perforation coating, and causing contact-free activation of said perforation coating.
 16. The method of claim 15, wherein furnishing said shrink-wrap film with a perforation coating comprises applying said perforation coating on an upper film surface of said film.
 17. The method of claim 15, wherein furnishing said film with a perforation coating comprises printing a coating on said film.
 18. The method of claim 17, wherein printing a coating on said film is carried out after securing said individual products to each other.
 19. The method of claim 15, wherein furnishing said film with a perforation coating comprises furnishing a perforation coating that absorbs a selected form of energy.
 20. The method of claim 19, further comprising heating said film by providing said selected form of energy to be absorbed by said film.
 21. The method of claim 15, furnishing said film with a perforation coating comprises furnishing a perforation coating that engages in a chemical reaction in response to a selected form of energy.
 22. The method of claim 13, wherein causing contact-activation of said film at said perforation area using an energy source comprises causing contact-free activation using electromagnetic radiation.
 23. The method of claim 13, wherein causing contact-activation of said film at said perforation area using an energy source comprises causing contact-activation using inductively-stored energy.
 24. The method of claim 13, wherein causing contact-activation of said film at said perforation area using an energy source comprises causing contact-activation using capacitively-stored energy.
 25. A manufacture comprising a packaging unit comprising individual products, and a shrink-wrap film, wherein said shrink-wrap film is furnished with a perforation area, wherein said individual products are combined into a product formation, wherein said products are secured to each other by said shrink-wrap film, and wherein said perforation area is susceptible to contact-free activation. 